Essential Plant Nutrients
Your Garden Must Have
You would not be very healthy without proper nutrition. Without 16 essential plant nutrients, neither would the plants in your garden. Three of these soil nutrients are snatched from the air; the other 13 are minerals your soil must provide.
Photosynthesis
Plants use light (usually the sun) to convert carbon dioxide in the air and water into starches and sugars. These starches and sugars are the food that the plant uses to produce new plant tissue for growth. Carbon, Hydrogen and Oxygen are the three non-mineral plant nutrients obtained through photosynthesis. These elements are taken in through the leaves of the plant. This process is beyond your control as the gardener, with one exception. Sun loving plants need full sun, and shade lovers don’t, to make the most of photosynthesis. The remaining 13 crucial plant nutrients can be divided into macronutrients or micronutrients. They are taken up primarily as soil nutrients, once dissolved into their chemical components and suspended in water by
soil microbes.
Plant Macronutrients
The big three are macronutrients because they are required in large quantities to help vegetation grow. These three are nitrogen (N) , phosphorus (P) and potassium (K) .On any fertilizer bag you will see
three numbers
separated by dashes, like 12-8-8 or 13-23-23. The first number always refers to the percentage of nitrogen (N) the product contains. The second number is the percentage of phosphorus (P), and the third potassium (K). Together they represent the N-P-K content of the fertilizer. A lawn fertilizer might read 24-10-10 because lawns require high amounts of nitrogen.
Miracle Gro
for your garden contains 15-30-15 because fruits, vegetables and flowers need more phosphorus to develop. Nitrogen About 78% of the earth’s atmosphere is nitrogen gas, but most plants can’t extract nitrogen directly from the air. It must be present in the soil for the roots to take it up, unless the plant is
foliar fed.
Nitrogen is necessary for strong leaf growth and good fruit set. If leaves begin to yellow, it is often a sign of too little nitrogen. Organic sources include
compost
,
manure
, bloodmeal, bonemeal, cottonseed meal and alfalfa meal. Phosphorus Phosphorus strengthens root systems and improves flowering, which means more fruit and more seed. It is essential to all living cells. Organic sources include rock phosphate, bonemeal, and cottonseed meal. Potassium This soil nutrient promotes strong stems and is crucial to cell division. It also strengthens against disease and reduces water requirements. Organic sources include greensand and wood ash, as well as compost. There are three more secondary macronutrients, Calcium (Ca) , Magnesium (Mg) and Sulfur (S) . While needed in less quantity than the big three, they are still essential to plant development: - Calcium improves cell wall structure and strength.
- Magnesium is crucial to chlorophyll production and photosynthesis.
- Sulfur produces proteins and promotes vigor, particularly in roots.
Organic sources include dolomite lime (used to raise
soil ph
), gypsum (used to lower soil ph), Epsom salts and
compost
(particularly if you add egg shells).
Plant Micronutrients
Man has also identified seven micronutrients or trace elements vital to plant development. Garden gnomes know several more, but they are naturally abundant in every soil so I won’t confuse you. The seven are:- Boron (B) - Improves sugar and carbohydrate production and availability of other nutrients.
- Chloride (Cl) - Improves plant metabolism.
- Copper (Cu) - Improves plant reproductive growth.
- Iron (Fe) - Required for chlorophyll production.
- Manganese (Mn) - Needed for both nitrogen and carbohydrate metabolism.
- Molybdenum (Mo) - Improves nitrogen uptake.
- Zinc (Zn) - Improves use of carbohydrates and sugars and regulates plant growth.
Many of these trace elements are present in adequate supply in most soils. That means they will be available in
composts
unless the
organic matter
was grown on deficient soils. But, absence of any of them can dramatically affect your garden. Other sources are ground oyster shell, seaweed, leaf mold and rock phosphate. Commercially prepared
fertilizers
contain the macronutrients and many also have guaranteed amounts of the micronutrients as well. Whether you garden organically or not, you must provide your garden with the necessary plant nutrients. Even if present, the availability of soil nutrients will depend on the proper
soil ph
. Happy gardening, Geefrank
What fertilizers are best for your garden?
Using commercial Organic Fertilizer.
How soil ph affects nutrient availability.
Return from Plant Nutrients to the Fertilizer page.
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